Presently, researches on technologies about electric vehicle charging facilities and industries of electric vehicle charging facilities have rapidly developed, and constructions of mobile charging projects have accelerated. The mobile charging devices nowadays mostly use new energy batteries, which act as key intermediate energy storage between energy supplementing and charging. The main technical problems encountered in research and development of the mobile charging device are variability of quantities of electricity needed by served objects, requirement of electric quantity balance of the intermediate energy storage and requirement of maximizing the output power of the intermediate energy storage device.
In a conventional mobile charging device product, certain energy storage battery pack is often used out earlies than other energy storage battery packs. In the mobile charging device product, all energy storage battery packs operate in parallel to one another, so the output power will become lower and the service time will become longer correspondingly, as a result, the service efficiency will become lower and demands of the charging orders distributed by an order system cannot be met.
In addition, in the conventional mobile charging device product, a fixed power charging mode is adopted, i.e. shares of the charging output power taken by each energy storage battery pack are specified in advance, and in all subsequent charging processes, all energy storage battery packs will output charging power according to the specified shares, so when a certain energy storage battery pack is used out earlier than other energy storage battery packs, said energy storage battery pack needs to be replaced, thus increasing the cost.